Zubrin on Moon, then Mars - Three essays, one link

Ad Astra · 2005-03-17 20:28:27

I briefly read Zubrin's trio and I've found many problems. His analysis is very simplistic and he prematurely rules out the possibility that "QQ" would reliably work.

It would be silly to assume you could launch four heavy EELV's in a month. The way to get around this is an Apollo-like solution: put storable propellants in the lander. Apollo used N2O4 and MMH; I prefer H2O2 and kerosene because it's less nasty to work with. You could keep the LSAM in lunar orbit (which according to Zubrin is unstable) for another month while waiting for the CEV to come.

QQ will avoid an Apollo 13 style accident. I've heard that NASA is going solar instead of fuel cells for the spaceship's power system for this very reason. Further, you can avoid docking the LSAM "lifeboat" with the CEV for the same reason that Mars Direct doesn't have a separate mothership and lander: just build redundant systems into the ship. The lifeboat was a redundant system. You don't need a lifeboat to duplicate all of the CEV's functions as long as you have redundant systems that are spaced far enough apart, so a common problem doesn't disable the backups.

Even if one in four missions fails, it doesn't mean loss of crew. There are more failure scenarios where the crew is saved than scenarios where the crew is killed. The mission could be scrubbed before EDS 1 pushes the LSAM to the moon. The LSAM or either EDS could blow up on the pad. Even if the CEV booster blew up, an escape system could save the crew.

I found it interesting that Zubrin's CEV would be so light (12 MT) and his LSAM so heavy. The Grumman engineers of the 60's did a marvelous job making the LEM as flimsy as possible to save weight in the near-weightless environment. This time around, NASA is looking at designs that are even more austere, like open cockpits.

There isn't enough space here to totally deconstruct Zubrin, but the point is that we can do the moon without an HLLV or direct landing. Perhaps the plan should be to get to the moon initially by QQ in the 2015-2020 time frame, then develop a new HLLV in time for Mars by 2030.

BWhite · 2005-03-17 21:49:28

Ad Astra, how do you define "do the moon"

Also, is there any extraction of lunar O2 in your vision? Or is that delayed as well?

What do we gain, big picture by doing the moon QQ style?

= = =

Edit: Is 2015 even remotely realistic if we do not cut back ISS obligations? 2014 is the first crewed flight of CEV.

There is little money for lander development until 2011.

Mars by 2030 is a fantasy because we need to build HLLV and all the HLLV infrastructure.

Pad 39? Gone!
VAB? Gone!
Crawler? Gone!

Doing the moon all-EELV means Mars is GONE at least until 2040 or later. . .

Edited By BWhite on 1111118013

Ad Astra · 2005-03-17 23:57:44

I'm not ADVOCATING an all-EELV approach, I'm just saying that it's doable. I would like us to get an HLLV, and if the budget can support an SDV, EELV's, and flights to the moon, I'm all for the SDV. If the budget won't allow it, all-EELV is the way it has to be.

I don't expect lunar flights by 2015 IF the manned CEV does not fly until 2014. That being said, the Spiral 1 CEV timetable could be sped up, dependent on funding. Realistically, I think 2018 is a reasonable date for human lunar return.

My vision of the moon does include use of lunar oxygen, but it is a capability that is built upon with successive missions rather than something we rely on for the initial missions. I also think lunar oxygen is irrelevant to Mars exploration because of the delta-V required to transport it.

My motivations for exploring the moon (in order of importance,) are:

1) Lunar solar power
2) Rare element / mineral mining
3) Science (radio telescope, early solar system remnants, etc)
4) Space tourism

GCNRevenger · 2005-03-18 00:47:56

Right on AdAstra, exactly. Good list about Lunar reasons, though I am dubious about the solar power given the transmission distance involved. I get the feeling that Bob was intentionally making those poor assumptions intentionally to make EELV look bad and SDV look good (he keeps saying that is will be cheaper because its bigger, thats not true).

The heavy LSAM makes sense though, since we will want bigger, heavier payloads then the old LEM offerd.

I will say it again, that unless we know with reasonable certainty that SDV or other for-the-Moon HLLV can be operated within budget, then EELV is the only viable option.

Pad 39? Gone!
VAB? Gone!
Crawler? Gone!

Are you sure this is a bad thing? All these things are expensive to operate, and as I have said before, manpower makes up for about 90% of the manned spaceflight budget (inc. ISS). NASA cannot afford to keep paying them and execute VSE. It is quite possible that NASA can't operate SDV cheaply enough because of all these facilities and jobs it requires to operate them.

Lunar LOX extraction is important, but it would be silly to require it for early missions. The first missions should purely be to shake down the system and do initial exploration (and scout a good base site). Lunar fuel extraction should be a medium-term goal to reduce the cost of running a Lunar base, not to try and sell to LEO customers... When Shuttle-II comes online sometime down the road, it would slap the Lunar LOX prices silly I bet.

Its obvious that we do need HLLV for a Mars trip, no question there, but I reject this idea that it needs to be built right now for the Moon or else we'll never get to Mars, because of the higher future pricetag of developing HLLV. Building a new rocket will not be that expensive versus the total cost of a Mars mission (easily above $50Bn for a worthwhile one).

If SDV can be done without killing NASA, great lets do it, sign the contract with United Space... but until we know, Mars or no Mars, SDV is off the table. When we're ready to go to Mars, we would just have to wait a little longer to build a clean-sheet rocket that is affordable.

BWhite · 2005-03-18 04:26:24

In my opinion, the mission critical task is to broaden the funding base.

It does not matter what we do, EELV, HLLV, whatever, if the American taxpayer remains the sole funding source, the American space program will wither and die.

The funding base needs to be diversified.

EELV only? The Russians can mount an MLV program far more cheaply than we can. Why play to their strength and our weakness?

Edited By BWhite on 1111141644

Gennaro · 2005-03-18 05:19:03

It does not matter what we do, EELV, HLLV, whatever, if the American taxpayer remains the sole funding source, the American space program will wither and die.

Sorry to hear that, but there is no other relevant source than US taxpayer money, right? Forget about space tourism and advertising, it will never catch on or in any event pay the billl to any meaningful degree.

Also, forget about PGM's for these early series of missions. The point should be to construct a functional moonbase core and infrastructure, so testing as many techniques related to extended presence as possible that will also (hopefully) provide handling experience for Mars and secondary to do science (which could be PGM related), should go into the mission goals.

Therefore, putting oxygen in situ production to practice from start, having both direct and future implications, appears to me an obvious part of the program as well as using heavy launchers for all the equipment and logistics required. At least if you don't want the Moon to turn into another ISS cost and construction nightmare that will never proceed to Mars. Zubrin's views appear totally sound to me.

PS: I suggested the possibility of lunar PGM's before this book came out which I haven't read. However, it appeared to me that PGM's would be related to mafic-ultramafic complexes created from lava flows following impactors, which like on Earth would mean digging considerably into the lunar crust to get it out. Setting up a mining operation the equivalent of Bushveldt is thus nothing to contemplate for the time being.

BWhite · 2005-03-18 05:32:28

=IF= there is no economic return from going to the Moon =THEN= there is no reason to return to the Moon, except to practice for Mars.

Or to play Emperor's New Space Program. :;):

= = =

Who said this:

# What option should NASA pursue in human space flight?
Accepting my premise that the proper goal of a publicly-funded space program is to enable the human settlement of the solar system, it becomes immediately clear that the relevant possibilities are few in number, and that we have not recently pursued any of them.

Or this:

It may not be impossible to consider returning to the moon, or going to Mars, without a robust heavy-lift launch capability, but it is certainly silly.

= = =

Those who favor EELV only, are you calling Michael Griffin out?

Forget Robert Zubrin (who is easy enough to attack personally)

Ad Astra, GCNRevenger, is Michael Griffin wrong?

Edited By BWhite on 1111145615

Gennaro · 2005-03-18 05:38:29

=IF= there is no economic return from going to the Moon =THEN= there is no reason to return to the Moon, except to practice for Mars.

Precisely. Just my non-expert opinion. Consider me a representative of the masses.
:;):

SpaceNut · 2005-03-18 06:36:25

Question: If a shuttle sized vehicle (SDV) were built on the moon, How long would it take to get to mars, how often could we have a valid launch window and would this make the infrastructure for Mars more of a possibility?

With this all in mind, What work has been really done with regards to the mars lander?
The Russian SCIENTISTS to START TESTING MODEL OF MANNED MARS LANDER
Is this just more vaporware?

Ad Astra · 2005-03-18 07:02:18

Those who favor EELV only, are you calling Michael Griffin out?
Forget Robert Zubrin (who is easy enough to attack personally)
Ad Astra, GCNRevenger, is Michael Griffin wrong?

Michael Griffin, in his previous position, was perfectly in his capacity to call for an HLLV. Now that he's going to be running NASA, he has a budget to worry about and a Congress that he must continually appease.

I acknowledge that the QQ method would be far more difficult than direct landings and surface rendezvous. But if congressional bean counters take the HLLV option off the table, I would rather have QQ than no moon mission at all. And Congress isn't the only bad guy here. If NASA and Boeing and LockMart want to build an SDV, they must learn to control costs so the US taxpayer can afford it.

My big beef with Robert Zubrin is the intellectual dishonesty he's using to advocate his big-booster position. He doesn't need to resort to trickery to lure me into the big-booster camp; why is he trying to pull the wool over the eyes of people who can't cut through his flimsy polemic? Either he's being dishonest with us or he's not a particularly good engineer, and I happen to believe the former.

GCNRevenger · 2005-03-18 07:18:16

Russian lander = Dinky wind tunnel toy model, big deal

Using the Moon to practice for Mars makes limited sense, and isn't worth all the expense of going there or learning to live there. The hardware and conditions will be so different that going to one isn't really a test for the other.

The Moon does enough scientific worth to go back on its own, the case for robot explorers is clearly weak given how much better people are at exploring. Nor can robots set up large telescopes.

Certainty of scientific bennefit, from learning about Earth's past and new "Earth noise free" astronomy... possibility of big future strateigic economic payoff by being the sole bulk supply of economically life-or-death elements within a 3-day flight... Certainty of being a tourist destination when Shuttle-II becomes practical.

Mining PGMs won't be as difficult as you make it sound... on Earth we have to dig for them because they are remnants of a large meteor which has been buried long ago. On the Moon, new rocks fall all the time, and are litterd across the landscape. With little weathering, these rocks are still there near the surface.

With abundant heat energy, driving off the oxides and melting the meteors down should not be too much trouble given the worth of the metal. 30MT of Carbon Monoxide is probobly on the high end of the range if you could do an pre-purifying step at the "smelter" and do a large batch all at once... Anyway, if it costs $80M to put that load of CO on the Moon, that tonne of PGMs would still be worthwhile if we run out here on Earth.

Oh, recycling rocket exhaust deposited in the Lunar dust isn't going to work, since the exhaust products are volitile.
---
As far as getting there... yes, if Griffin has no credible evidence to assert that SDV will be affordable, then yeah I am "calling him out." At best incompetance, at worst a underhanded grab to keep The Army in business.

"The Russians can mount an MLV program far more cheaply than we can. Why play to their strength and our weakness?"

No they can't. That is not true. The fact of the matter is that Russia has no rockets nor can upgrade any rocket to the minimum required size. Even the heaviest Angara model is too small. The cost savings of keeping the mission in fewer, bigger pieces and not delaying it to wait for the Russian rockets to catch up (since they would need to launch twice as many!) will largely make up for the price differential.

In any event, your continued parroting of the wonders of selling out our space program to Russia is beginning to be as the proverbial broken reccord Bill... even if the costs were zero, and the rockets were free, NASA would be stupid to use them... The political cost of "going Russian" would exceed any material cost savings, and infact American rockets would be "cheaper" politically enough that the government will not balk at their higher price.

BWhite · 2005-03-18 08:06:40

As far as getting there... yes, if Griffin has no credible evidence to assert that SDV will be affordable, then yeah I am "calling him out." At best incompetance, at worst a underhanded grab to keep The Army in business.

Lets not shift the goalposts.

Griffin said returning to the Moon without robust heavy lift is silly. SDV is only one HLLV option. If SDV cannot be done within our budget and if no other HLLV is within our budget then attempting to return to the moon with an insufficient budget is silly.

- - -

Unless we are returning to the Moon to open it up for commerce, I do not agree that the science only justifies the expense and I strongly prefer Mars. Lunar commerce, as proposed by Wingo? Sure, I support that 100%

Once again, take permanent settlement off the table (with resource exploitation being part of "settlement") and I strongly favor robots only for pure science driven exploration.

Therefore unless crewed missions bring us closer to permanent settlement, I believe they are a waste of tax dollars.

LOX extraction is job #1 for a lunar return as it will give the biggest "bang" in economic return of any lunar resource program. If it is not part of the first mission, why pay for the first mission at all?

BWhite · 2005-03-18 08:16:24

Of course, I believe we could add $ 5 - 10 billion to the lunar return exploration budget simply by selling media rights and hyping the televised landings.

Mars would garner more.

= = =

Edit to add: Walk away from ISS. Orbiter never flies again. Then we could afford HLLV.

What HLLV is best? SDV or clean sheet? Good question.

But lunar return without HLLV is silly.

Edited By BWhite on 1111156781

SpaceNut · 2005-03-18 08:45:50

Another reason for the Lox processing is for Man continued presence for with out it we are in the ISS boat of always needing to resupply it.
We must also look at other fuel types that do not rely on Lox /LH2 or water derived. These are more valueable to man for surviability under the lunar conditions.

Gennaro · 2005-03-18 09:28:07

GCNRevenger wrote:

Using the Moon to practice for Mars makes limited sense, and isn't worth all the expense of going there or learning to live there. The hardware and conditions will be so different that going to one isn't really a test for the other.

Of course, but we are not the ones having decided to go to the Moon, the United States President has. I believe there is no argument about the desire for a lunar telescope array. If there is any part of Astronomy me and the masses are really excited about, it's exploration and biosphere hunting in the stellar neighbourhood.

Mining PGMs won't be as difficult as you make it sound... on Earth we have to dig for them because they are remnants of a large meteor which has been buried long ago. On the Moon, new rocks fall all the time, and are litterd across the landscape. With little weathering, these rocks are still there near the surface.

Sounds better than I had dared to expect. Maybe I should read that book.

Bill White wrote:

Of course, I believe we could add $ 5 - 10 billion to the lunar return exploration budget simply by selling media rights and hyping the televised landings.
Mars would garner more.

Perhaps, but it would be a one time bonus. In contrast to GCN though, I firmly believe that tourism won't be profitable. The people willing to put up astronomical sums to see a grey dusty desert on the Moon followed by another desert on Mars are likely to be easily counted, even if you throw in a view of the gravel pit you mentioned.

Had the Moon featured winged Lunarians and Venus steaming emerald green jungles, it would have been another matter of course. Could be space nuts like us just have a hard time realizing that.

SpaceNut wrote:

If a shuttle sized vehicle (SDV) were built on the moon, How long would it take to get to mars, how often could we have a valid launch window and would this make the infrastructure for Mars more of a possibility?

Why on Earth would you like to do such an outrageously complicated and messy thing like building a shuttle derived rocket on the Moon?

It wouldn't facilitate Mars infrastructure, but make it more difficult, since you'd have to go to the Moon in the first place, requiring a total Delta V of 6.3 to reach Mars rather than 4.5 if you went straight from LEO, hence increasing fuel requirements. The launch windows would, as far as I know, be identical since these are determined by Mars' relative position to Earth (which is the same for the Moon).

John Creighton · 2005-03-18 09:45:46

It wouldn't facilitate Mars infrastructure, but make it more difficult, since you'd have to go to the Moon in the first place, requiring a total Delta V of 6.3 to reach Mars rather than 4.5 if you went straight from LEO, hence increasing fuel requirements. The launch windows would, as far as I know, be identical since these are determined by Mars' relative position to Earth (which is the same for the Moon).

I really get tiered of hearing this. You don’t fly to the moon and then fly to mars. The lunar ship would meat the earth ship in earth moon space and then go to mars. This saves the problem of having to land on the moon. Still it would take considerable infrastructure on the moon to build a spaceship. Especially one as big as the shuttle.

GCNRevenger · 2005-03-18 09:56:43

If we are going to the Moon, we might as well set up a Lunar astronomy station on the dark side... I think that such an operation is beyond the abilities of robots, so people would have to go and handle assembly. They should probobly stay long enough to make sure the thing works too after they are done putting it together. Power supply would be Solar+Fuel Cell and RTGs for supplimentary (replaced every few years during instrument upgrade).

Shifting goal posts? Griffin appears to be already set on the idea of going the Shuttle Derived route. Right now, Shuttle costs almost $1Bn per flight, and this figure would have to be cut in HALF (preferably by 2/3rds) to make SDV affordable to fly, reguardless of its development costs. I don't think its asking too much for Griffin to have more then a feeling or huntch that this can likly be done... I want more then empty assurances, I want accounting & engineering studies to show that it can be done.

HLLV in the form of a clean sheet rocket would be nice, but the price tag for such a project will be fairly steep, especially if we don't really need it. I think that it is possible to set up a small Lunar base soley with EELV, because of the small minimum size of crew vehicles and high performance of modern engines for landers. Remember, SDV will basically be launching the same size of payload as EELV (perhaps a little larger) and a TLI stage of similar size, they'll just be riding together as opposed to seperatly. Return to the Moon without HLLV is NOT silly if the HLLV price-tag is too high.

NASA is also going to work within a basically zero-sum budget for a long time most likly, and there is nothing wrong with this. NASA gets enough money, they just have to be forced to spend it wisely. $7Bn a year goes to the d*** Shuttle and ISS, and trimming another billion or two from elsewhere would add up.

Lunar ISRU of some sort is vital to any long-term presence on the Moon, no argument there, but it isn't practical to use it for early flights. Sending return fuel from Earth isn't that hard if all you are returning is crew and boxes of rocks and computer disks. Only later will we need it.

I never said tourism would be in itself profitable, but with Shuttle-II providing order-of-magnetude lower launch costs, then using its low marginal cost for additional flights to fly tourists/TLI fuel/supplies is low enough to make such a proposition possibly worthwhile to help offset Lunar base costs. Or at least fly them to LEO to mitigate Shuttle-II costs.

GCNRevenger · 2005-03-18 10:03:17

I am becomming less and less of a fan of "Mad Bob" Zubrin...

"My big beef with Robert Zubrin is the intellectual dishonesty he's using to advocate his big-booster position. He doesn't need to resort to trickery to lure me into the big-booster camp; why is he trying to pull the wool over the eyes of people who can't cut through his flimsy polemic? Either he's being dishonest with us or he's not a particularly good engineer, and I happen to believe the former."

...Is a good summary of his worsening behavior. Smart people who do know that he is trying to do will take him less and less seriously. He is becomming a liability to advocacy of manned Mars expeditions.

"...At least if you don't want the Moon to turn into another ISS cost and construction nightmare that will never proceed to Mars. Zubrin's views appear totally sound to me."

Again, a rush to heavy lift in the form of SDV or a low-development-cost clean sheet HLLV would be the worst possible thing, and would trap us in "ISS mode" just as badly. The Moon is also an entirely different construction setting then the ISS, on the Moon it is much more practical to build things in a modular fasion, because construction is so much easier (and everything stays where you put it).

Gennaro · 2005-03-18 10:04:16

Another reason for the Lox processing is for Man continued presence for with out it we are in the ISS boat of always needing to resupply it.
We must also look at other fuel types that do not rely on Lox /LH2 or water derived. These are more valueable to man for surviability under the lunar conditions.

I don't believe there are any. The Moon almost entirely lacks nitrogen and carbon, which means that things like methane, ammonia and hydrazine won't be available.

Although reserves of water ice is a bonus we don't really need it for rocket fuel, unless perhaps we want the Moon to be a staging area for points beyond Mars. If we transport hydrogen by the bulk we can react it with ilmenite to create water which then can be turned into oxygen and hydrogen at will.
The process is said to be rather energy intensive, so I would presume nuclear reactors would be a good thing to ship to the Moon.

Gennaro · 2005-03-18 10:17:39

GCNRevenger and Ad Astra, I would love to read more in detail what your gripes are with Bob. You see, I'm just an enthusiast without the proper science or engineering education and to me Zubrin simply sounds so darn sensible most of the time. If there are bogus arguments, I must admit I lack the ability to decode them. Would you care to share the knowledge?

Again, a rush to heavy lift in the form of SDV or a low-development-cost clean sheet HLLV would be the worst possible thing, and would trap us in "ISS mode" just as badly.

Why? With heavy lift, you can carry more in fewer runs that are safer. When we eventually want to go RLV, we will also need heavy launchers to lift SSTO's into position on Mars, the Moon or wherever.

Gennaro · 2005-03-18 10:44:34

I really get tiered of hearing this. You don’t fly to the moon and then fly to mars. The lunar ship would meat the earth ship in earth moon space and then go to mars.

I believe this is incorrect. Just going from LEO to lunar orbit would still require a Delta V of 4.1 (3.2 for trans-lunar injection + 0.9 to capture into Low Lunar Orbit). This is practically the same as going directly from LEO to MLO, which is generally described as a Delta V of 4.2 (4.5 if you include landing on Mars).

If you add the Delta V for going from lunar orbit to Mars orbit and the extra infrastructure and logistics on the Moon, it appears to be a fundamentally flawed proposition.

GCNRevenger · 2005-03-18 11:31:19

For chemical rocket fuel, you need two things, an oxidizer and a reducer (fuel) agent. On the Moon, there is plenty of oxidizer locked up as metal oxides in the omnipresent dust, which can be liberated by heating or chemical means.

However, the Moon lacks much in the way of a useful reducing agent. No carbon, little or no hydrogen, nothing that is both potent and stable as a pure liquid. In fact, the only really potent reducing agent that is just laying around is the Aluminum in the soil, and designing an engine that burns Aluminum dust would be difficult and probobly suffer in performance. An Alumiun/LOX slurry monopropellant is possible, but it would be dangerous since the fuel and oxidizer would be in intimate contact. A minor accident could cause an explosion... It would be easier to haul Hydrogen or Methane from Earth to mix with Lunar LOX.

-----------------------------------------------------------------------

What have been Space Bob's offences? A short list...

-Designing a Mars mission that is unrealisticly light weight and cheap, which I believe he knows this and is trying to get it started and hope nobody notices until it is too late to cancel it. Insufficent everything, HAB/ERV are too small, reactor is too light, main rover is too light, science payload too light, insufficent radiation shielding, and aerobrake shield too probobly. The crew is too small, and there is not enough margin for unforseen mass penalties or future upgrades.

-Seemingly uninterested in crew psychological health. His own lack thereof concerning Mars missions indicates to me that this is a larger problem then he gives credit.

-Selling his Mars mission design as more capable then it really is, that MarsDirect has no future beyond MarsDirect, no upgrade path is practical, and MarsDirect would be horribly inefficent for basic crew rotations.

-Lately, he has started selling SDV as a cheap solution to all our problems. He does not have sufficent grounds to assert that SDV will be nessesarrily cheap enough to fly.

-Smearing EELV use for a Lunar program, assuming things that are silly or unreasonable in order to make it apear unworkable.

-Basically being hell-bent to put our boots on Mars right now, and saying anything or ignoring anyone who might get in his way, with no thought to the future other then dreamy notions of large Mars bases.

SpaceNut · 2005-03-18 11:31:48

My thought for building shuttle mass sized vehicles is to allow for a greater mass to reach mars from a moon built facility since the moons gravity well is only 1/6th that of Earths.

RobS · 2005-03-18 13:47:58

The problem with building rockets on the moon is that you would need to spend hundreds of billions to design, transport, and install the infrastructure there to build the rockets that can be made more cheaply on Earth. Perhaps we will be building rockets on the moon in the 22d century, but that will be true only if we can launch stuff cheaply enough into low earth orbit and the moon acquires economic momentum of its own. I suspect building rocket parts on Mars and assembling them on Phobos or Deimos will make more sense; Mars has a wider range of ores available, has carbon, nitrogen, and hydrogen in abundance for making plastics, and Phobos provides a zero-gee body with radiation shielding, stability, water, and solar energy.

The moon is useful short term under these circumstances:

1. We use ion engines to move equipment slowly out of the Earth's gravity well. These items can be accumulated at L1, the gravitational stability point between the Earth and moon.

2. Polar ice is reasonably abundant and the ability to exploit it is reasonably cheap. This is possible and we will know the abundance much better in the next few years.

Under this scenario, pieces of a Mars transit vehicle would be slowly moved to L1; fuel for trans-Mars injection would be flown up from the lunar north or south pole; the crew would fly up from Earth quickly in a small, chemically propelled vehicle like a CEV; the Mars ship would then execute a small delta-v (about 0.5 km/sec) that would send it flying towards the earth; and just a few hundred miles about the surface, moving at almost escape velocity, the engines would fire and lunar fuel would be burned for trans-Mars injection.

This scenario is also well designed for the use of EELVs for a Mars mission, because the mass of fuel that has to be lifted to low earth orbit is radically reduced. Each Mars vehicle would require one large (maybe 40 tonne) EELV launch, and a third launch would be needed to send up two solar-powered ion tugs and fuel (xenon is godawful expensive, ten million per tonne; maybe argon can be used efficiently by then). A 40-tonne vehicle going to Mars would only need about 10 tonnes of lunar LOX/LH2 for trans-Mars injection.

But it will be a few years before we will know whether this scenario is a reasonable one.

-- RobS

Michael Bloxham · 2005-03-18 18:29:02

What have been Space Bob's offences? A short list...
-Designing a Mars mission that is unrealisticly light weight and cheap, which I believe he knows this and is trying to get it started and hope nobody notices until it is too late to cancel it. Insufficent everything, HAB/ERV are too small, reactor is too light, main rover is too light, science payload too light, insufficent radiation shielding, and aerobrake shield too probobly. The crew is too small, and there is not enough margin for unforseen mass penalties or future upgrades.

You know what? Maybe your right. But if you are, there are a few things that might be done. The most obvious: Reduce the crew size from 4 to 3. Whoopee, all problems solved! In addition, smaller less critical components of the Mars Direct hardware could be launched separately on an MLV (or an additional launch of an SDV?).

-Seemingly uninterested in crew psychological health. His own lack thereof concerning Mars missions indicates to me that this is a larger problem then he gives credit.

Okay, this is one argument I simply can't agree with. Crew psychological health is way over-rated, IMO. During transit, the crew will have access to the internet, huge music libraries, movies, a nights sky full of stars, each others company, etc. And during their 1.5 year surface stay, they will have a comfortable day/night cycle, freedom to roam on the surface, a stimulating work routine, etc. Damn, I'll volunteer!

-Selling his Mars mission design as more capable then it really is, that MarsDirect has no future beyond MarsDirect, no upgrade path is practical, and MarsDirect would be horribly inefficent for basic crew rotations.

I have yet to see a mission plan that is more capable than Mars Direct. Do you have something in mind, GCNRevenger?
Zubrin repeats in his book: Destination drives Transportation. I would personally like to get there before we start thinking about permanent human habitation and terraformation, which are about the only two things Mars Direct doesn't cover.

-Lately, he has started selling SDV as a cheap solution to all our problems. He does not have sufficent grounds to assert that SDV will be nessesarrily cheap enough to fly.

Damnit! I am so sick of hearing this! Why is it so damn critical SDV must be 'cheap enough to fly'? Is the space shuttle cheap enought to fly? Was the Saturn V cheap enough to fly? What is cheap enough to fly? Again, stop obsessing over launch costs and look at the bigger picture.

-Smearing EELV use for a Lunar program, assuming things that are silly or unreasonable in order to make it apear unworkable.

Yes, and I don't blame him 'cause its the damn truth.

Basically being hell-bent to put our boots on Mars right now, and saying anything or ignoring anyone who might get in his way, with no thought to the future other then dreamy notions of large Mars bases.

Yes, he is hell bent (I will give you that one!), but how can he put thought to something that, most optimistically, might occur 50 years or more from now? He will not even be alive. And in all likelyhood, neither will you

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#51 2005-03-17 20:28:27

Re: Zubrin on Moon, then Mars - Three essays, one link

#52 2005-03-17 21:49:28

Re: Zubrin on Moon, then Mars - Three essays, one link

#53 2005-03-17 23:57:44

Re: Zubrin on Moon, then Mars - Three essays, one link

#54 2005-03-18 00:47:56

Re: Zubrin on Moon, then Mars - Three essays, one link

#55 2005-03-18 04:26:24

Re: Zubrin on Moon, then Mars - Three essays, one link

#56 2005-03-18 05:19:03

Re: Zubrin on Moon, then Mars - Three essays, one link

#57 2005-03-18 05:32:28

Re: Zubrin on Moon, then Mars - Three essays, one link

#58 2005-03-18 05:38:29

Re: Zubrin on Moon, then Mars - Three essays, one link

#59 2005-03-18 06:36:25

Re: Zubrin on Moon, then Mars - Three essays, one link

#60 2005-03-18 07:02:18

Re: Zubrin on Moon, then Mars - Three essays, one link

#61 2005-03-18 07:18:16

Re: Zubrin on Moon, then Mars - Three essays, one link

#62 2005-03-18 08:06:40

Re: Zubrin on Moon, then Mars - Three essays, one link

#63 2005-03-18 08:16:24

Re: Zubrin on Moon, then Mars - Three essays, one link

#64 2005-03-18 08:45:50

Re: Zubrin on Moon, then Mars - Three essays, one link

#65 2005-03-18 09:28:07

Re: Zubrin on Moon, then Mars - Three essays, one link

#66 2005-03-18 09:45:46

Re: Zubrin on Moon, then Mars - Three essays, one link

#67 2005-03-18 09:56:43

Re: Zubrin on Moon, then Mars - Three essays, one link

#68 2005-03-18 10:03:17

Re: Zubrin on Moon, then Mars - Three essays, one link

#69 2005-03-18 10:04:16

Re: Zubrin on Moon, then Mars - Three essays, one link

#70 2005-03-18 10:17:39

Re: Zubrin on Moon, then Mars - Three essays, one link

#71 2005-03-18 10:44:34

Re: Zubrin on Moon, then Mars - Three essays, one link

#72 2005-03-18 11:31:19

Re: Zubrin on Moon, then Mars - Three essays, one link

#73 2005-03-18 11:31:48

Re: Zubrin on Moon, then Mars - Three essays, one link

#74 2005-03-18 13:47:58

Re: Zubrin on Moon, then Mars - Three essays, one link

#75 2005-03-18 18:29:02

Re: Zubrin on Moon, then Mars - Three essays, one link

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